Switch and circuit breaker



Feb. 2, 19,32. K, WlLCKENS 1,843,351

' SWITCH AND CIRCUIT BREAKER Filed May 17, 1928 Patented Feb. 2, 1932UNITED STATES PAH-:Nr ori-lcs .KURT wmcxmrs, or PHILADELPHIA,PENNSYLVANIA.' AssIeNon 'To HEINNANN marmo COMPANY, or PHILADELPHIA,PENNSYLVANIA, A. CORPORATION or PENNSYLVANIA SWITCH AND CIRCUIT BREAXERAppucmnnmea nay 17, 192s. seria No. 278,521.

My invention is'designed; to provide a switch and circuit breaker whichautomatically opens a circuitl immediately upon -the occurrence of anabnormal overload and automatically opens the circuit after a brief lagupon the maintenance of a slight overload,

but which will permit the brief flow of al harmless momentary overloadof limited amount such-as occurs when a motor or electrical appliance iscut in. If, however, the overload of limited amount continues, thecircuit is not only broken but the subsequent closure and maintenancethereof is prevented until the current is reduced to normal or theprotected device has Ahad an opportunity to cool. In the, preferredembodiment of my invention, the circuit controlling switch blade isnormally operable by a handle connected with the blade through linksforming a toggle joint adapted to be brokento open the switch by anarmature actuated by electromagnetic force. The armature is sopositioned relatively'to the source of electromagnetic fforce as to bebe ond the attractive' heated by a sustained flow of excessive cur-irent, moves the armaturevinto the zone of attractive power of thefmagnetic field resulting from the passage of any overload.

Consequently there is a lag in the operation of the device when theoverload is of limited amount. Such lag affords a brief time for thereturn of the current to normal without breaking the circuit, but if thecurrent does not return to normal within the period allowed, the circuitis broken and cannot thereafter be maintained until vthe thermostati'cdevice has cooled suiciently to cause the removal of the armature fromthe attractive power vof the-magnetic field, thereby affording time forcooling the windings of the movtor o r the like.

Iappear from the following description and the accompanying drawings inillustration thereof.

n In the drawings, Fig. lis a transverse sectional view througha casingcontaining a switch and circuit breaker embodyin my improvements, withpart of the brac et supporting the operating parts broken away; Fig. 2is a front elevation thereof with the cover removed; Fig. 3 showsdetached perspective views of switch blade members; Fig. 4 is a`detached perspective view of the armature; and Fig. 5 is a. diagrammaticwiring diagram of the device.

As illustrated in the drawings, an insulating base 1, preferably housedwithin a casing 2 having an apertured hinged cover 3,

has iixed thereto a bracket 4 from which depends a'solenoidcoil l5. Atube 6 is secured in the center of the coil and is capped by anadjustable cap.7. An armature 8, having a non-magnetic nose piece 9, ismovable longitudinally in the tube( and its normal vertical positzionmay be regulated by adjusting the cap l A blade carrier 10 is journalledon the-pin.

11 carried by the bracket 4 which contains a slot for the passage of thetail of the carrier, and a block 12 on the pin 115is housed between thebifurcations of the carrier and [provides an anchorage for a bent spring13 Secured to the block by a pin or rivet 11. The spring 13 projectsupward beyond the carrier 10, and has fixed thereto a detachable contact14. The outer end of the spring is positioned relative to the carrier 10by a pivot 15 on which is journalled a U-shancd link 16 pivotl, allyconnected-by a pivot 17 with a link 18.

A pintle 19 connects the link 18 with a hub 20 provided with a handle 20and journalled on the pin 21 carried by the bracket 4.

An arm 22 projecting from the link 18 is provided with a foot 23disposed in alignment with the armature 8 when the switch is closed. Anear 24 projectin from the link 16 has a locked set screw 25 t readedtherein members 16 and 18 toward the bracket 4.

A contact 26 fixed to the base 1 within the asbestos lined shield 27 ispositioned 4for engagement by the contact 14 and is connected with aline terminal 28 through a suitable conductor `26 preferably recessed inthe base 1.

A load terminal or bracket 29 fixed to the baseboard 1 has a conductingpost 30 projecting therefrom on which is coiled a thermostatic conductor3l comprising connected laminated sheets of metals welded together andhaving different coeiiicients of expansion. The end of the thermostaticdevice 31 projects through slots 7 in the vcap 7 beneath the bottom ofthe armature 8, which normally rests thereon. The bracket 29 may beconnected by a suitable conductor 29 with an appropriate load (notshown)from which a return wire runs to the terminal 32 of the neutral wire ofthe system. The thermostatic device 31 is connected with an end 5 of thecoil 5, and the other end 5 of the coil is connected with a binding post5a which is l connected by the conductor 13 with the blade The hub 20has a segment cut from the periphery thereof oppositethe handle 20 toform stops 20a and 20?) which engage with the web of the bracket 4 tolimit the throw of the handle. The remaining peripheral segment of thehub forms a closure for the opening in the lid 3 in either position ofthe handle. Should the lid 3 he opened while the handle 20 is in the uper position it is thrown by the engagement tierewith of the lid to thelower position indicated in dotted lines to open the switch.

Any desired number of circuit breakers may be mounted upon a base plateor panel, but preferably' they are mounted in pairs connected vwith asingle return wire, as shown in Fig. 2.

When a handle 20 is thrown to the upper position shown Ain full lines inFig. 1, it acts through the hub and link mechanism described to rock theswitch carrier l0 toward the base 1 against the action of the spring 13and bring the contact 14 into engagement with the contact 26. The stop20a and screw 25 are so positioned that when the switch is closed theaxes of the pintles 21, 19, 17 and 15 are not in a straight line, thepintle 17 being slightly nearer to the bracket 4 than would be acorresponding point in a straight line connecting the pintles 21 and 15.

When normal current flows from the line it passes through the terminal28, conductor 26', contact 26, contact 14, spring 13, conductor 13',binding post 5a, coil 5, flexible lead 5', thermostatic device 31, post30, bracket 29, conductor 29', terminal 32 tol ground.

The load, return wire and non-magnetic nose 9 may be adjustedlongitudinally in the botto'm Lor/"magnetic portion of the armature 8which normally lies below the portative force of the magnetic eldcreated by the passage of normal current through the coil 5; the device31 having such conductivity that it is not heated or bent by the flow ofnormal current.

The portative force of the magnetic field resulting from a slightoverload is insufficient' to lift the armature 8 from its normalposition at the bottom of the tube 6, but the continued flow of suchoverloadthrough the inember 31 heats the metals thereof and expands themunequally thereby causing the coiled portion thereof to elevate theprojecting end. The magnetic portion of the armature 8 is thereby liftedinto a more intense zone of the magnetic field of the coil 5, whichattracts the armature and moves the non-magnetic nose 9 thereof againstthe foot 23 with sutlicient force to break the joint between the links16 and 18 by throwing the pin 17 beyond dead center and permitting thespring 13 to open the switch.

It will, therefore, be seen that a momentary irelatively small overload,such as occurs in starting a motor or other electrical appliance, willnot break the circuit until such overload has persisted for such periodas is required to heat the device 31, which may be so adjusted as tomove upward before damage is `done to the insulation of the appliancebeing protected. y

If the switch is closed while the part 31 is still heated and there isany overload, the attraction of the solenoid causes the armature toimmediately break the toggle joint and open the switch.

When an abnormal overload occurs, such as results from a short circuitor static discharge, likely to cause immediate damage, the magneticiield created by the .passage thereof through the coil 5 is sufficientlystrong to immediately attract the armature 8 and cause it to break thetoggle joint without awaiting the heating of the element 31.

Having described my intention, I claim:

1. A switch and circuit breaker comprising a switch, a toggle connectedwith said switch, a handle connected with said toggle, an armature foroperating said toggle, a solenoid coil surrounding and actuating saidarmature and a bi-metallic thermostatic strip having a section movabletoward and from a plane normal to the axis of said solenoid coil, saidarmature being positioned relative to said Solenoid by the movement ofsaid section.

2. A switch and circuit breaker comprising a switch, a toggle connectedwith said switch, a handle connected with said toggle, a core foroperating said toggle, a solenoid coil surrounding and actuating saidcore and a coil of bi-metallic lthermostatic metal having a. fixed axialend and a free projecting end, said core being positioned relative tosaid solenoid by the movement of said free projecting end of said coil.

3. A switch and cir-cuit breaker comprising a switch and a fulcrurnedhandle, a springless togglehaving its ends pivotally connected with saidhandle and switch, a core movable into engagement with said member tobreak said toggle, a solenoid coil surrounding and operating said core,a guideway extending axially of said coil at the opposite end thereoffrom said toggle, and a thermostatic member having a section housed insaid guideway andl movable therein toward and from said coil, forvarying the position of said core relatively to said solenoid coil.

4. A switch and circuit breaker comprising a bracket having recesses atthe 4ends thereof and an aperture between said recesses, a solenoid coildepending from said bracket and having anl axial passage aligned Withsaid bracket aperture, a slotted tube depending from said solenoid coiland having therein a core with a non-magnetic nose fixed thereon andnormally occupying said axial coil passage, a coil of thermostatic metalhaving an axial end fixed and a projecting free end movable verticallyin the slots of said tube to position said core relatively to said coil,afulcrumed member oscillatablein one of said bracket recesses, a springswitch blade connected with said member, an oscillatory handleoscillatable in the other of said bracket recesses, and a toggleconnecting said handle and vmember and comprising a lbell-crank shapedmember having one arm thereof disposed in the path of movement of thenose of said core, and a link pivotally connected with the apex of saidbell-crank, said link having an extension preventing breaka e in onedirection in the joint between said ellcrank and link.

5. A switch andcircuit breaker comprising a switch blade, a toggle foroperating said switch blade and comprising a pair of links one of whichis connected with said switch blade, a handle connected with the otherof said links, a solenoid coil containing an axial passagey insubstantial alignment with the knee of said toggle, a core movable insaid passage to break said toggle and having thereon a non-magnetic nosenormall occupying the passage of said coil and projected therefrom bysaid core upon-the excitation of said coil, a guideway extending axiallyof said coil and normally housing said core, and a thermostatic devicehavin a section housed in said guideway and mova le therein towardmetallic thermostatic metal having an axial end fixed adjacent to theend of said solenoid coil opposite to said toggle and having a freeprojecting end movable toward and from a plane normal to the axis ofsaid solenoid coil, and trip means for operating said toggle andcomprising an armature movable in said axial opening and a non-magneticmember between said toggle and armature, said armature being positionedby the free end of said thermostatic coil and actuated by the magneticflux of the solenoid coil.

In testimony whereof I have hereunto set my hand this 16th day of May,1928.

KURT WILCKENS.

